Students learn principally through interactions with people (teachers and peers) and instructional materials (textbooks, workbooks, instructional software, web-based content, homework, projects, quizzes, and tests). But education policymakers focus primarily on factors removed from those interactions, such as academic standards, teacher evaluation systems, and school accountability policies. It’s as if the medical profession worried about the administration of hospitals and patient insurance but paid no attention to the treatments that doctors give their patients.

Choosing better instructional materials “should be relatively easy, inexpensive, and quick,” compared to improving teacher quality, write Russ Whitehurst and Matthew Chingos. They urge states, the federal government, nonprofit groups and philanthropists to fund research on effectiveness. That would start by collecting data on what instructional materials schools are using.